This invention relates to a water purifying apparatus for purifying tap water supplied to a detached house or an apartment house.
A water purifying apparatus for drinking water generally comprises an adsorber such as activated carbon and/or a filter selected from various types of filtering media and serves to remove various pollutants, such as suspended solids, Protozoa, chlorine odor, musty odor, and organic compounds, remaining in tap water. If the water purifying apparatus is installed in an apartment house requiring a large amount of treated water, use is generally made of a large-scale filtering medium, magnetic effect, far-infrared ceramics, and natural stones. The size of the water purifying apparatus widely differs depending upon the amount of treated water required in each application.
In the water purifying apparatus, the tap water is made to pass through the activated carbon or the filter to remove the pollutants. Thus, the tap water is treated into the treated water. While the treated water is reserved in the water purifying apparatus before it is supplied as the drinking water, various bacteria or microorganisms may possibly grow and propagate, particularly around the activated carbon or the filter where the pollutants are adsorbed or trapped. In order to kill or destroy the bacteria and the microorganisms, heating or ultraviolet radiation is typically used.
However, if the large-scale filtering medium is used, the water purifying apparatus is increased in size and complicated in structure. Thus, the use of the additional filtering medium is disadvantageous in view of the cost and the maintenance. In addition, flow resistance is great and blinding often occurs to deteriorate the filtering ability.
On the other hand, use of an ultraviolet radiator comprising a plurality of ultraviolet lamps is also disadvantageous in the following respect. Generally, the ultraviolet lamps have a short life as a guaranteed cumulative use period. In other words, the ultraviolet lamps will be burned out after a relatively short period of use. If some of the lamps are burned out and the water purifying apparatus is kept operated, the sterilizability is degraded. In order to avoid this, the ultraviolet lamps must be frequently exchanged. Thus, the use of the ultraviolet radiator has a difficulty in maintenance. Even if either the additional filtering medium or the ultraviolet radiator is used, the growth of bacteria and microorganisms in the water purifying apparatus is inevitable if the treated water is less frequently used or is not used for a long time.